Krodharaja Achala (English: the Immovable One, King of the Wrathful). Achala is a meditational deity in wrathful appearance. He is not a protector. There are however forms of Achala that are included in the Anuttarayoga groupings of the Ten Wrathful Ones. Explanations and descriptions for these deities including Achala are found in the Tantras such as Guhyasamaja, Hevajra, Chakrasamvara, Vajrabhairava, etc. In the context of these Tantras, and the Twelve Wrathful Ones, Achala is a protector deity as part of a group of protectors within a larger system, or cycle, of practice.

Tantras specifically devoted to Achala can be found in the Kriya, Charya and Anuttarayoga classifications. In the Kriya classification there are several Tantras that teach the rituals and meditations of Achala. The Siddhaikavira Tantra is one of the most popular - catalogued by the Sakyas as a Charya Tantra - also known as the White Manjushri Tantra. From this last Tantra Achala, in a kneeling posture, takes on his primary role as a remover of obstacles and secondly as the special remover of obstacles for the meditational practices related to Manjushri. The continuation of this practice of linking the two deities, Manjushri and Achala,is still found in the Sakya Tradition and likely others (as yet undocumented). (See Tantra Classifications).

In the Kadam Tradition of Atisha, Achala is counted as one of the four principle deities (Kadam Lha Shi): [1] Akshobhya, [2] Avalokiteshvara, [3] Tara and [4] Achala. In this configuration of four, Achala has the same role as a meditational deity and remover of obstacles.

Of the two Kriya Tantra practices, the Achala depicted in a kneeling posture was continued through many traditions but specially through the Sakya Tradition following the commentary by Lobpon Sonam Tsemo (1142-1182). The commentary is still in use today as the principal explanatory text. The practice of Achala in a standing posture was popularized by both Lord Atisha (982-1054) the founder of the Kadampa School followed by Mitra Yogin (12th - 13th century) famous for the text known as the Mitra Gyatsa.

In the higher Tantras of Anuttarayoga there are three, possibly more, Tantras specific to Achala. The most famous of these Tantras is the Chandamaharoshana where the deity is in a kneeling posture while embracing a consort, surrounded by a retinue of eight mandala figures.